Apparatus for separating magnetizable castings from casting moulds of sand or similar materials

ABSTRACT

An apparatus for removing magnetizable castings from a mould of foundry sand comprises a plurality of magnets mounted in a casing and spring biassed towards a basic position therein. The magnets are collectively movable towards the casting exposed in the mould and individually adjustable against the spring bias to the surface shape of the casting so that at least a substantial number of magnets simultaneously contact the casting. In this position the magnets are locked relative to the casing and are collectively retracted, thereby extracting the casting from the mould.

United States Patent [191 J orgensen et al.

[ Dec. 2, 1975 1 1 APPARATUS FOR SEPARATING MAGNETIZABLE CASTINGS FROMCASTING MOULDS OF SAND OR SIMILAR MATERIALS [75] Inventors: I-IemmingKristian Jorgensen,

Klampenborg; Marius Gunnergaard, Lyngby, both of Denmark [73] Assignee:Dansk Industri Syndikat A/S,

Herlev, Denmark [22] Filed: June 18, 1974 [21] Appl. N0.: 480,554

[30] Foreign Application Priority Data July 9, 1973 Denmark 3813/73 [52]US. Cl 164/404; 214/1 BT [51] Int. Cl. B22D 29/00; B251 3/00 [58] Fieldof Search 164/131, 344, 404, 403,

[56] References Cited UNITED STATES PATENTS 2/1916 Walpole 269/8 X11/1949 Pressman 269/8 2,672,664 3/1954 Sudziarski 164/146 2,754,7087/1956 Peterson 269/266 X 2,882,771 4/1959 Blazek 269/266 X 3,107,40210/1963 Hunter.... 164/403 3,627,020 12/1971 Taccone 164/344 X 3,807,6824/1974 Catinella 164/404 X FOREIGN PATENTS OR APPLICATIONS 1,230,6345/1971 United Kingdom 164/146 Primary Examiner-Francis S. HusarAssistant Examiner-John S. Brown Attorney, Agent, or Firm-Imirie, Smiley& Linn [57] ABSTRACT An apparatus for removing magnetizable castingsfrom a mould of foundry sand comprises a plurality of magnets mounted ina casing and spring biassed towards a basic position therein. Themagnets are collectively movable towards the casting exposed in themould and individually adjustable against the spring bias to the surfaceshape of the casting so that at least a substantial number of magnetssimultaneously contact the casting. In this position the magnets arelocked relative to the casing and are collectively retracted, therebyextracting the casting from the mould.

5 Claims, 3 Drawing Figures U.. Patent Dec. 2, 1975 APPARATUS FORSEPARATING MAGNETIZABLE CASTINGS FROM CASTING MOULDS OF SAND OR SIMILARMATERIALS BACKGROUND OF THE INVENTION The invention relates to anapparatus for separating magnetizable castings from casting moulds ofsand or similar materials at the end of a guiding track on which thecasting moulds, with castings therein, are placed closely together in arow and are advanced stepwise towards a knocking-out station at whichthe mould material is caused to drop onto a conveyor after the castingshave been removed.

The apparatus is primarily intended for use in connection with foundryequipment of the kind operating with a mould consisting of uniform mouldparts presenting at least one pouring cavity at each joint in the mouldand being produced successively from foundry sand which in a chamber iscompressed between a pair of opposed plates which carry semi-patternscorresponding to the castings to be produced. After having been socompressed, the mould part is displaced onto the guiding track alignedwith the chamber and is caused to join the row of earlier produced mouldparts which at the same time are advanced one step forward on theguiding track. As required, one or more cores can be placed in thepouring cavity, which is still open, in the mould part added last. Whenthe pouring operation proper has taken place, the casting mouldcontinues its movement of advance through a cooling section of asuitable length and then arrives at the knockingoutstation where thecastings and the mould part material can be separated from each other ona conventional knocking-out grate.

Another possibility of separating castings and mould material from eachother consists in removing the castings from the mould while the latteris still located on the guiding track. By this means the castings may betreated in a gentler manner and, in addition, various environmentaldisadvantages, such as a high noise level and inconvenience caused bydust, may be avoided or reduced.

SUMMARY OF THE INVENTION The main object of the invention has been toprovide an apparatus which makes it possible to perform such a removalof the castings magnetically and in such a way that one and the sameapparatus should be applicable for removing castings of literallyspeaking any optional shape and size.

The apparatus according to the invention is characterized in that at theknocking-out station a plurality of magnets are provided which from astarting position are movable first collectively in the directiontowards the freely exposed end of the row of casting moulds and nextindividually in dependence on the shape of the surface of the castingsfacing the magnets, until each of the plurality of magnets is in contactwith said surface, means being provided to subsequently lock the magnetstogether and means to collectively move them back towards their startingposition. During or after the termination of this return movement thecastings can be released from the magnets and be delivered for furthertreatment by means of a separate conveyor.

Due to their individual mobility the total number of magnets, or at anyrate a sufficient number thereof, can

jointly engage the castings effectively, and the subsequent interlockingof the magnets ensures the maintenance of this engagement during theremoval of the castings from the mould and during their transport to thedelivery position. It can thus be taken for granted that the totalmagnetic force is distributed evenly between the total number of magnetsor a large number thereof, which is a presupposition for thesatisfactory functioning of the apparatus, since the tractive forceexerted by each individual magnet will usually be too small for securelyholding the castings.

In order to further improve the holding fast of the castings, eachmagnet may aftere having after into contact with the castings beindividually rotatable around an axis at right angles to its contactsurface. By such a rotary movement the magnet will be able to scratchaway sand, if any, at the point of contact with the castings, which is acondition for the establishment of direct contact between the magnet andthe castings.

In a practical embodiment of the apparatus according to the inventionthe magnets are mounted in a common casing, which is displaceabletowards and away from the freely exposed end of the row of castingmoulds, and are separately displaceable in the same direction inrelation to the casting between a basic position advanced towards therow of casting moulds and a retracted position, and in addition they arespring biased towards the basic position. In this basic position thevarious magnets will nonnally have their fronts or active faces locatedin one and the, same plane which is at right angles to the direction ofdispplacement, and in most cases the different parts of the surface ofthe castings facing the magnets will be spaced at unequal distances fromthe said plane, that is to say from the magnets to be brought intocontact with the different parts of the castings. When the common casingis displaced over a length, which at least corresponds to the largestone of the said distances and preferably is somewhat larger, all of thenumber of magnets will successively be brought into contact with thecastings and next be pressed back relative to the casing against theaction of the spring bias. In the position which the magnets have herebyassumed, the various magnets can be interlocked, expediently by beingindividually locked to the casing, and the casing can then be displacedback, during which movement the magnets carry the castings along withthem. After the castings have been released from the magnets, theinterlocking of the latter can be eliminated, the spring bias thencausing the magnets to be once more brought into the starting positionor basic position so as to be ready for another operation.

The invention will now be more fully described with reference to thediagrammatical drawing.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a side elevational view,partially in vertical section, of an embodiment of the apparatusaccording to the invention with the magnets in the starting position orbasic position,

FIG. 2 is a view similar to FIG. 1 and shows part of the apparatus,likewise in side elevation and partially in vertical section, after themagnets have engaged the casting, and

FIG. 3 is a sectional view of the casing of the apparatus with a singlemagnet, shown in longitudinal section.

DESCRIPTION OF THE PREFERRED EMBODIMENT FIGS. 1 and 2 show the dischargeend of a guiding track 1 which supports a casting mould consisting of anumber of identical mould parts 2 holding a casting 3 at each joint 4 inthe mould. In the embodiment shown, the guiding track 1 is terminatedwith a short section comprising a frame 5 which carries a hook 6 forholding back the casting 3 which is exposed in the end of the castingmould after the preceding mould part 2 has been pushed out over the endof the guiding track 1 and has dropped onto a conveyor 7. The hook 6forms one arm of a bell crank, the other arm of which is connected to ahydraulic or pneumatic cylinder 8 which serves for moving the hook 6between the holding position shown in FIG. 1 and the released positionshown in FIG. 2. In order that the hook 6 may always engage the casting3 correctly, the frame 5 is adjustable forwards and backwards inrelation to the guiding track 1, depending on the thickness of the mouldparts 2. This adjustability has in the drawing been indicated by atoothed rack 9 on the underside of the frame 5 engaging a pinion 10,FIG. 1, which can be turned by means of a hand wheel 11, FIG. 2, and canbe locked in the position desired.

Aligned with the freely exposed end of the casting mould a box-shapedcasing 12 is provided which by means of a bracket 13 is suspended from acarriage 14 which is displaceable on a pair of horizontal, parallelguides 15, between which a drive cylinder 16 is mounted, the piston rod17 of which engages the carriage 14. The box-shaped casing 12 contains aplurality of parallel, rod-shaped magnets 18, which will be described ingreater detail in the following and which together cover an areacorresponding to a substantial portion of the cross-section of thecasting mould. Between this mould and the casing 12 a stripper plate 19is provided which has a hole for each of the magnets 18 and which issuspended displaceably from the guides by means of an additionalcarriage 20. The stripper plate 19 is displaceable towards and away fromthe casing 12 by means of a drive cylinder 21 supported by the bracket13 of the casing. In the position shown in FIG. 1, the casing 12 withthe magnets 18 is located above a conveyor 22 for carrying away thereleased castings 3.

FIG. 3 shows parts 23 and 24 of the rear and front walls of the casing12, and a cylindrical guide tube 25 secured in these walls. A supportingbody 26 is accommodated displaceably in the guide tube 25, and at itsfront end this body is provided with a permanent magnet 27 which isisolated from the supporting body 26 by means of non-magneticintermediate piece 28. The part of the supporting body 26 locatedbetween the walls 23 and 24 has a circumferential recess 29 containing amagnetizable powder or grain material, and the guide tube 25 issurrounded by a magnet coil 30 which, when energized, actuates thepowder or the grains in the recess 29 and thereby locks the supportingbody 26 to the guide tube 25.

In the embodiment shown, the permanent magnet 27 is carried by a spindle31 which is journalled in the supporting body 26 and the rear portion ofwhich is designed with a steep-pitch thread 32 engaging one or moreprojections, not visible, in a sleeve 33 which is secured to the rearwall 23 of the casing and in the position shown in FIG. 3 extendsslightly forwards past the rear end of the spindle 31. The sleeve 33 issurrounded by a pressure spring 34 which with its ends abuts against thewall 23 of the casing and the rear end of the supporting body 26,respectively.

With the components in the starting position shown in FIG. 1, the drivecylinder 21 is first actuated so that the stripper plate 19 is pulled intowards the casing 12, thus causing the magnets 18 to project throughthe holes of the stripper plate. Next, the drive cylinder 16 is actuatedfor displacement of the casing 12 and the stripper plate 19 towards thecasting mould, and during the last part of this movement the variousmagnets 18 get into contact with the casting 3 as shown in FIG. 2. Aftera magnet 27 has got into contact with the casting 3, its support 26 willduring the continued displacement of the casing 12 be pressed backrelative to the casing against the action of the spring 34, and thesteep-pitch thread 32 in the spindle 31 will thereby cause a revolvingmovement to be imparted to this spindle, and thereby to the magnet 27,so that the front face of the magnet will scratch away or mill awayparticles of sand, if any, on the casting.

After the termination of the forward movement of the casing 12, that isto say in the position in FIG. 2, the hook 6 is released by an actuationof the drive cylinder 8, and the magnet coils 30 are energized, so thatall of the magnets 18 are now locked to the casing. By means of thedrive cylinder 16 the casing 12 is now returned to the starting positionshown in FIG. 1 while carrying along the casting 3, and in this positionthe casting can be released from the magnets by means of the stripperplate 19, so that the casting drops onto the conveyor 22. Subsequently,the current to the magnet coils 30 can be switched off, so that thesprings 34 urge the various magnets to their basic position shown inFIGS. 1 and 3. Simultaneously, the drive cylinder 8 causes the hook 6 toreturn to the position shown in FIG. 1, so that during the next step ofadvance of the casting mould the hook will plough into the surface ofthe succeeding mould part 2 and engage the next piece of casting.

Even if the two conveyors 7 and 22 for the moulding sand and thecastings, respectively, are shown as a single grate conveyor with apartition 35 between the two advancing tracks, it will be obvious thattwo entirely separate conveyors of any optional kind may be used in thisplace.

For the sake of completeness it should be mentioned that electromagnetsmay be used instead of the permanent magnets 27, and that the locking ofthe magnets 18 in the position shown in FIG. 2 may be effected in otherways than by means of the magnet couplings shown, the sole condition tobe fulfilled by the locking mechanism being that it can be actuated andreleased at will with the magnets in any position, dependent on theshape of the surface of the castings, and in the released positionpermits the individual displacement of the magnets.

In addition it should be pointed out that the movement of the magnets 18collectively need not be a movement of displacement, but may for example,be a pivoting movement around an overhead axis which is either parallelto or at right angles to the direction of advance of the casting mould.

We claim:

1. An apparatus for separating magnetizable castings from a sand moldconsisting of a succession of mold parts which are horizontally advancedstepwise to a mold breaking station at which each mold part issuccessively allowed to drop away so as to expose its respective castingcomprising a carrier frame mounted in front of said mold breakingstation so as to be displaceable towards and away therefrom, a pluralityof magnets mounted in said carrier frame and protruding towards saidmold breaking station, said magnets being individually displaceablerelative to said carrier frame between an extended basic position and aretracted position, means biasing said magnets towards said basicposition and permitting their individual retraction as they are broughtin contact with the exposed casting by displacement of said carrierframe towards said mold breaking station, and means for locking saidmagnets in their retracted positions relative to said carrier frameduring the displacement thereof away from said mold breaking stationwhereby said casting is pulled and separated from a remaining mold part.

2. An apparatus as claimed in claim 1, wherein said magnets during theirretraction movements are individually rotatable around axesperpendicular to their front faces in contact with the casting.

3. An apparatus as claimed in claim 1, further including a stripperplate disposed between said carrier frame and said mold breakingstation, said stripper plate having apertures for receiving said magnetsand being displaceable both in conjunction with and relative to saidcarrier frame.

4. An apparatus as claimed in claim 1, wherein each magnet has asupporting body which is displaceable in a guide tube in said carrierframe and which, after the contact of the magnet with the casting hasbeen established, can be locked in the guide tube by the actuation of amagnet coil surrounding the guide tube, in connection with amagnetizable powder or grain material in one or more recesses in thesupporting body.

5. An apparatus as claimed in claim 4, wherein the supporting body istubular and contains a rotatable spindle which is rigidly connected tothe magnet and is provided with a steep-pitch thread engaging one ormore guiding projections fixed in the carrier frame for bringing aboutthe turning of the magnet during its retraction in relation to thecarrier frame.

1. An apparatus for separating magnetizable castings from a sand moldconsisting of a succession of mold parts which are horizontally advancedstepwise to a mold breaking station at which each mold part issuccessively allowed to drop away so as to expose its respective castingcomprising a carrier frame mounted in front of said mold breakingstation so as to be displaceable towards and away therefrom, a pluralityof magnets mounted in said carrier frame and protruding towards saidmold breaking station, said magnets being individually displaceablerelative to said carrier frame between an extended basic position and aretracted position, means biasing said magnets towards said basicposition and permitting their individual retraction as they are broughtin contact with the exposed casting by displacement of said carrierframe towards said mold breaking station, and means for locking saidmagnets in their retracted positions relative to said carrier frameduring the displacement thereof away from said mold breaking stationwhereby said casting is pulled and separated from a remaining mold part.2. An apparatus as claimed in claim 1, wherein said magnets during theirretraction movements are individually rotatable around axesperpendicular to their front faces in contact with the casting.
 3. Anapparatus as claimed in claim 1, further including a stripper platedisposeD between said carrier frame and said mold breaking station, saidstripper plate having apertures for receiving said magnets and beingdisplaceable both in conjunction with and relative to said carrierframe.
 4. An apparatus as claimed in claim 1, wherein each magnet has asupporting body which is displaceable in a guide tube in said carrierframe and which, after the contact of the magnet with the casting hasbeen established, can be locked in the guide tube by the actuation of amagnet coil surrounding the guide tube, in connection with amagnetizable powder or grain material in one or more recesses in thesupporting body.
 5. An apparatus as claimed in claim 4, wherein thesupporting body is tubular and contains a rotatable spindle which isrigidly connected to the magnet and is provided with a steep-pitchthread engaging one or more guiding projections fixed in the carrierframe for bringing about the turning of the magnet during its retractionin relation to the carrier frame.